• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.25 no.2
• /
• pp.24-31
• /
• 2011

The purpose of this study is to find an efficient way using dimmable LED lamps to describe specific target illuminance and color temperature. This study used 14 dimmable LED lamps as same or different color temperature. The method of study is to measure of electric power consumption using different color temperature of dimmable LED lamps that were combination of two or three dimmable LED lamps by simultaneously dimming. Through this method, the electric power consumption was compared with all combinations of the illuminance and color temperature.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.58 no.3
• /
• pp.516-522
• /
• 2009

The dimmable magnetic ballast which applies the variable inductor needs a switching process for the dimming process, and it consists of mechanical relays because of costs and reliabilities. However, it is hard to operate with correct timing in mechanical relay, so relays reduce their own life time in inductive applications. Moreover this creates a destructive problem at the switching process. The life time reduction of relays means the life time reduction of the ballast. Thus, in this paper, we described the problem at the witching process in the dimmable magnetic ballast with a variable inductor, which consists of relays and the soft AC switching method in order to solve the problems. As result, we achieved the improvement of the life time and reliability of the ballast.

• Journal of the Optical Society of Korea
• /
• v.20 no.1
• /
• pp.29-35
• /
• 2016

This paper deals with a design method and capacity loss of an efficient multi-level modulation scheme for dimmable visible light communications (VLC) systems that use light-emitting diodes (LEDs) with efficiency droop. To this end, the impact of such an impairment on dimmable VLC is addressed with respect to multi-level modulations based on pulse-amplitude modulation (PAM) via data-rate optimization formulation.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2004.05a
• /
• pp.313-317
• /
• 2004

This paper shows the structure of a control System for Fluorescent fin Dimming Ballasts. The control system is composed of phase angle controller, a transducer, many dimmable ballasts. For the implementation of the control system, We made a controller and the transducer that transform the phase angle controlled signal into the DC level. we used the conventional dimmable ballast In this ballast, dimming control is achieved by varying the switching frequency that is controlled by the external DC level. This has non-linear illumination characteristics as the dimming control. Therefore we compensate characteristics using the transducer proposed in this paper. We measured the illumination of two FL-28 lamps with dimming controller.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.24 no.10
• /
• pp.13-20
• /
• 2010

Until now, dimmable fluorescent luminaires has been widely used for dimming systems, and LED is currently attracting attentions as a alternative lamp due to environmental problem issues. LED, one of eco-friendly high efficiency lamp, has advantage that dimming is easy than fluorescent luminaire. But there have been not enough research on technical development and application for LED dimming. Therefore, to analyze luminous quantity of dimmable LED, the illuminance, color temperature, luminance, and current were measured in the whole range of dimming. In the results of this study, the dimmable LED of various types showed a similar trend in the changed luminous quantity by dimming.

• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.1142-1143
• /
• 2007

A new scheme of dimmable ballast system for the electrodeless fluorescent lamp is proposed. The proposed scheme is composed of the conventional ballast system and the wireless communication part using an EPLD. As a result, the proposed system has a dimming control capability by wireless communication technology. In this paper, wireless dimming control system for electrodeless fluorescent lamp was introduced.

• Current Optics and Photonics
• /
• v.2 no.6
• /
• pp.532-539
• /
• 2018

Multiple LED arrays can be utilized in visible-light communication (VLC) to improve communication efficiency, while maintaining smart illumination functionality through dimming control. This paper proposes a modulation scheme called "Spatial Intensity Modulation" (SIM), where the effective number of turned-on LEDs is employed for data modulation and dimming control in VLC systems. Unlike the conventional pulse-amplitude modulation (PAM), symbol intensity levels are not determined by the amplitude levels of a VLC signal from each LED, but by counting the number of turned-on LEDs, illuminating with a single amplitude level. Because the intensity of a SIM symbol and the target dimming level are determined solely in the spatial domain, the problems of conventional PAM-based VLC and related MIMO VLC schemes, such as unstable dimming control, non uniform illumination functionality, and burdens of channel prediction, can be solved. By varying the number and formation of turned-on LEDs around the target dimming level in time, the proposed SIM scheme guarantees homogeneous illumination over a target area. An analysis of the dimming capacity, which is the achievable communication rate under the target dimming level in VLC, is provided by deriving the turn-on probability to maximize the entropy of the SIM-based VLC system. In addition, a practical design of dimmable SIM scheme applying the multilevel inverse source coding (MISC) method is proposed. The simulation results under a range of parameters provide baseline data to verify the performance of the proposed dimmable SIM scheme and applications in real systems.

• Proceedings of the KIEE Conference
• /
• 2004.11c
• /
• pp.487-489
• /
• 2004

As the electrodes are not needed, the electrodeless lamps using the induction discharge have a long lifetime and are robust against the variable output condition of a ballast. This paper proposed a dimmable resonant inverter for the electrodeless lamps. The proposed resonant inverter formed a half bridge inverter adopted FWM to control the average output power of the inverter and the illumination of a lamp. In this paper, the proposed dimming algorithm was described and the prototype experimental setup for 100W electrodeless lamps was carried out to verify the validity of the proposed dimming method.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.24 no.12
• /
• pp.9-16
• /
• 2010

In this paper, we have proposed a new dimmable magnetic ballast for HID(High Intensity Discharge) lamps consisted of AC switches to variate inductance value by using Silicon Controlled Rectifiers and the isolated zero current detector on inductor. Conventional dimming ballast has used relays or Solid State Relays in AC switches. However, a relay is difficult to zero current switching, because it has long operating time(10[ms]), and price competitiveness of SSR is very low. The proposed AC switches are suitable to switch at zero inductor current and it is accurately detected by using a opto-coupler. SCR is cheaper than SSR, and it is suitable to switch at zero inductor current because SCR is automatically turned off under holding current at no gate signal. Operating principles, simulation results and experimental results of the proposed ballast are described.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.1361-1365
• /
• 2005

This paper presents a high-frequency electronic ballast for HID lamps. A new fixed frequency dimming method with low EMI features is developed in this research. The proposed electronic ballast has the advantages of high power density, simple circuit and low EMI features. The circuit operating principle and design procedures are described in detail. A laboratory prototype was built and tested. The simulation and experimental waveforms verify the feasibility of the proposed scheme.